The purpose of this study was to ascertain the status and patterns of pinworm Enterobius vermicularis infection among preschool children in Jeollanam-do from 2023 to 2025. Further, it aimed to assess changes in infection rates during the implementation of the test-and-treatment strategy. Cellophane tape swabs were collected from 12,608 children aged 0–6 years enrolled in daycare or kindergarten facilities in 8 cities and counties of Jeollanam-do. The samples were examined under a light microscope to diagnose pinworm infection. The overall infection rate over the 3-year period was 0.22% (28/12,608). The annual infection rate declined continuously from 0.35% in 2023 to 0.06% in 2025 (trend P<0.05). The infection rate did not vary significantly with sex (P>0.05), but was significantly higher in the 4–6 year age group (P<0.05), and was highest in Jangheung-gun (0.65%) and Goheung-gun (0.37%). The overall infection rate in this study was substantially lower than previously reported. However, this may represent a transient phenomenon reflecting environmental or behavioral factors associated with this specific period. Therefore, continuous monitoring is necessary.